~bzr-pqm/bzr/bzr.dev

# Copyright (C) 2005, 2006 Canonical Ltd

#

# This program is free software; you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation; either version 2 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

"""Base implementation of Transport over http.

There are separate implementation modules for each http client implementation.

"""

from cStringIO import StringIO

import errno

import mimetools

import os

import posixpath

import re

import sys

import urlparse

import urllib

from warnings import warn

# TODO: load these only when running http tests

import BaseHTTPServer, SimpleHTTPServer, socket, time

import threading

from bzrlib import errors

from bzrlib.errors import (TransportNotPossible, NoSuchFile,

                           TransportError, ConnectionError, InvalidURL)

from bzrlib.branch import Branch

from bzrlib.trace import mutter

from bzrlib.transport import (

    get_transport,

    register_transport,

    Server,

    smart,

    Transport,

    )

from bzrlib.transport.http.response import (HttpMultipartRangeResponse,

                                            HttpRangeResponse)

from bzrlib.ui import ui_factory

def extract_auth(url, password_manager):

    """Extract auth parameters from am HTTP/HTTPS url and add them to the given

    password manager.  Return the url, minus those auth parameters (which

    confuse urllib2).

    """

    assert re.match(r'^(https?)(\+\w+)?://', url), \

            'invalid absolute url %r' % url

    scheme, netloc, path, query, fragment = urlparse.urlsplit(url)

    if '@' in netloc:

        auth, netloc = netloc.split('@', 1)

        if ':' in auth:

            username, password = auth.split(':', 1)

        else:

            username, password = auth, None

        if ':' in netloc:

            host = netloc.split(':', 1)[0]

        else:

            host = netloc

        username = urllib.unquote(username)

        if password is not None:

            password = urllib.unquote(password)

        else:

            password = ui_factory.get_password(prompt='HTTP %(user)@%(host) password',

                                               user=username, host=host)

        password_manager.add_password(None, host, username, password)

    url = urlparse.urlunsplit((scheme, netloc, path, query, fragment))

    return url

def _extract_headers(header_text, url):

    """Extract the mapping for an rfc2822 header

    This is a helper function for the test suite and for _pycurl.

    (urllib already parses the headers for us)

    In the case that there are multiple headers inside the file,

    the last one is returned.

    :param header_text: A string of header information.

        This expects that the first line of a header will always be HTTP ...

    :param url: The url we are parsing, so we can raise nice errors

    :return: mimetools.Message object, which basically acts like a case 

        insensitive dictionary.

    """

    first_header = True

    remaining = header_text

    if not remaining:

        raise errors.InvalidHttpResponse(url, 'Empty headers')

    while remaining:

        header_file = StringIO(remaining)

        first_line = header_file.readline()

        if not first_line.startswith('HTTP'):

            if first_header: # The first header *must* start with HTTP

                raise errors.InvalidHttpResponse(url,

                    'Opening header line did not start with HTTP: %s' 

                    % (first_line,))

                assert False, 'Opening header line was not HTTP'

            else:

                break # We are done parsing

        first_header = False

        m = mimetools.Message(header_file)

        # mimetools.Message parses the first header up to a blank line

        # So while there is remaining data, it probably means there is

        # another header to be parsed.

        # Get rid of any preceeding whitespace, which if it is all whitespace

        # will get rid of everything.

        remaining = header_file.read().lstrip()

    return m

class HttpTransportBase(Transport, smart.SmartClientMedium):

    """Base class for http implementations.

    Does URL parsing, etc, but not any network IO.

    The protocol can be given as e.g. http+urllib://host/ to use a particular

    implementation.

    """

    # _proto: "http" or "https"

    # _qualified_proto: may have "+pycurl", etc

    def __init__(self, base):

        """Set the base path where files will be stored."""

        proto_match = re.match(r'^(https?)(\+\w+)?://', base)

        if not proto_match:

            raise AssertionError("not a http url: %r" % base)

        self._proto = proto_match.group(1)

        impl_name = proto_match.group(2)

        if impl_name:

            impl_name = impl_name[1:]

        self._impl_name = impl_name

        if base[-1] != '/':

            base = base + '/'

        super(HttpTransportBase, self).__init__(base)

        # In the future we might actually connect to the remote host

        # rather than using get_url

        # self._connection = None

        (apparent_proto, self._host,

            self._path, self._parameters,

            self._query, self._fragment) = urlparse.urlparse(self.base)

        self._qualified_proto = apparent_proto

    def abspath(self, relpath):

        """Return the full url to the given relative path.

        This can be supplied with a string or a list.

        The URL returned always has the protocol scheme originally used to 

        construct the transport, even if that includes an explicit

        implementation qualifier.

        """

        assert isinstance(relpath, basestring)

        if isinstance(relpath, unicode):

            raise InvalidURL(relpath, 'paths must not be unicode.')

        if isinstance(relpath, basestring):

            relpath_parts = relpath.split('/')

        else:

            # TODO: Don't call this with an array - no magic interfaces

            relpath_parts = relpath[:]

        if relpath.startswith('/'):

            basepath = []

        else:

            # Except for the root, no trailing slashes are allowed

            if len(relpath_parts) > 1 and relpath_parts[-1] == '':

                raise ValueError("path %r within branch %r seems to be a directory"

                                 % (relpath, self._path))

            basepath = self._path.split('/')

            if len(basepath) > 0 and basepath[-1] == '':

                basepath = basepath[:-1]

        for p in relpath_parts:

            if p == '..':

                if len(basepath) == 0:

                    # In most filesystems, a request for the parent

                    # of root, just returns root.

                    continue

                basepath.pop()

            elif p == '.' or p == '':

                continue # No-op

            else:

                basepath.append(p)

        # Possibly, we could use urlparse.urljoin() here, but

        # I'm concerned about when it chooses to strip the last

        # portion of the path, and when it doesn't.

        path = '/'.join(basepath)

        if path == '':

            path = '/'

        result = urlparse.urlunparse((self._qualified_proto,

                                    self._host, path, '', '', ''))

        return result

    def _real_abspath(self, relpath):

        """Produce absolute path, adjusting protocol if needed"""

        abspath = self.abspath(relpath)

        qp = self._qualified_proto

        rp = self._proto

        if self._qualified_proto != self._proto:

            abspath = rp + abspath[len(qp):]

        if not isinstance(abspath, str):

            # escaping must be done at a higher level

            abspath = abspath.encode('ascii')

        return abspath

    def has(self, relpath):

        raise NotImplementedError("has() is abstract on %r" % self)

    def get(self, relpath):

        """Get the file at the given relative path.

        :param relpath: The relative path to the file

        """

        code, response_file = self._get(relpath, None)

        return response_file

    def _get(self, relpath, ranges):

        """Get a file, or part of a file.

        :param relpath: Path relative to transport base URL

        :param byte_range: None to get the whole file;

            or [(start,end)] to fetch parts of a file.

        :returns: (http_code, result_file)

        Note that the current http implementations can only fetch one range at

        a time through this call.

        """

        raise NotImplementedError(self._get)

    def get_request(self):

        return SmartClientHTTPMediumRequest(self)

    def get_smart_medium(self):

        """See Transport.get_smart_medium.

        HttpTransportBase directly implements the minimal interface of

        SmartMediumClient, so this returns self.

        """

        return self

    def readv(self, relpath, offsets):

        """Get parts of the file at the given relative path.

        :param offsets: A list of (offset, size) tuples.

        :param return: A list or generator of (offset, data) tuples

        """

        ranges = self.offsets_to_ranges(offsets)

        mutter('http readv of %s collapsed %s offsets => %s',

                relpath, len(offsets), ranges)

        code, f = self._get(relpath, ranges)

        for start, size in offsets:

            f.seek(start, (start < 0) and 2 or 0)

            start = f.tell()

            data = f.read(size)

            if len(data) != size:

                raise errors.ShortReadvError(relpath, start, size,

                                             actual=len(data))

            yield start, data

    @staticmethod

    def offsets_to_ranges(offsets):

        """Turn a list of offsets and sizes into a list of byte ranges.

        :param offsets: A list of tuples of (start, size).  An empty list

            is not accepted.

        :return: a list of inclusive byte ranges (start, end) 

            Adjacent ranges will be combined.

        """

        # Make sure we process sorted offsets

        offsets = sorted(offsets)

        prev_end = None

        combined = []

        for start, size in offsets:

            end = start + size - 1

            if prev_end is None:

                combined.append([start, end])

            elif start <= prev_end + 1:

                combined[-1][1] = end

            else:

                combined.append([start, end])

            prev_end = end

        return combined

    def _post(self, body_bytes):

        """POST body_bytes to .bzr/smart on this transport.

        :returns: (response code, response body file-like object).

        """

        # TODO: Requiring all the body_bytes to be available at the beginning of

        # the POST may require large client buffers.  It would be nice to have

        # an interface that allows streaming via POST when possible (and

        # degrades to a local buffer when not).

        raise NotImplementedError(self._post)

    def put_file(self, relpath, f, mode=None):

        """Copy the file-like object into the location.

        :param relpath: Location to put the contents, relative to base.

        :param f:       File-like object.

        """

        raise TransportNotPossible('http PUT not supported')

    def mkdir(self, relpath, mode=None):

        """Create a directory at the given path."""

        raise TransportNotPossible('http does not support mkdir()')

    def rmdir(self, relpath):

        """See Transport.rmdir."""

        raise TransportNotPossible('http does not support rmdir()')

    def append_file(self, relpath, f, mode=None):

        """Append the text in the file-like object into the final

        location.

        """

        raise TransportNotPossible('http does not support append()')

    def copy(self, rel_from, rel_to):

        """Copy the item at rel_from to the location at rel_to"""

        raise TransportNotPossible('http does not support copy()')

    def copy_to(self, relpaths, other, mode=None, pb=None):

        """Copy a set of entries from self into another Transport.

        :param relpaths: A list/generator of entries to be copied.

        TODO: if other is LocalTransport, is it possible to

              do better than put(get())?

        """

        # At this point HttpTransport might be able to check and see if

        # the remote location is the same, and rather than download, and

        # then upload, it could just issue a remote copy_this command.

        if isinstance(other, HttpTransportBase):

            raise TransportNotPossible('http cannot be the target of copy_to()')

        else:

            return super(HttpTransportBase, self).\

                    copy_to(relpaths, other, mode=mode, pb=pb)

    def move(self, rel_from, rel_to):

        """Move the item at rel_from to the location at rel_to"""

        raise TransportNotPossible('http does not support move()')

    def delete(self, relpath):

        """Delete the item at relpath"""

        raise TransportNotPossible('http does not support delete()')

    def is_readonly(self):

        """See Transport.is_readonly."""

        return True

    def listable(self):

        """See Transport.listable."""

        return False

    def stat(self, relpath):

        """Return the stat information for a file.

        """

        raise TransportNotPossible('http does not support stat()')

    def lock_read(self, relpath):

        """Lock the given file for shared (read) access.

        :return: A lock object, which should be passed to Transport.unlock()

        """

        # The old RemoteBranch ignore lock for reading, so we will

        # continue that tradition and return a bogus lock object.

        class BogusLock(object):

            def __init__(self, path):

                self.path = path

            def unlock(self):

                pass

        return BogusLock(relpath)

    def lock_write(self, relpath):

        """Lock the given file for exclusive (write) access.

        WARNING: many transports do not support this, so trying avoid using it

        :return: A lock object, which should be passed to Transport.unlock()

        """

        raise TransportNotPossible('http does not support lock_write()')

    def clone(self, offset=None):

        """Return a new HttpTransportBase with root at self.base + offset

        We leave the daughter classes take advantage of the hint

        that it's a cloning not a raw creation.

        """

        if offset is None:

            return self.__class__(self.base, self)

        else:

            return self.__class__(self.abspath(offset), self)

    @staticmethod

    def range_header(ranges, tail_amount):

        """Turn a list of bytes ranges into a HTTP Range header value.

        :param offsets: A list of byte ranges, (start, end). An empty list

        is not accepted.

        :return: HTTP range header string.

        """

        strings = []

        for start, end in ranges:

            strings.append('%d-%d' % (start, end))

        if tail_amount:

            strings.append('-%d' % tail_amount)

        return ','.join(strings)

    def send_http_smart_request(self, bytes):

        code, body_filelike = self._post(bytes)

        assert code == 200, 'unexpected HTTP response code %r' % (code,)

        return body_filelike

class SmartClientHTTPMediumRequest(smart.SmartClientMediumRequest):

    """A SmartClientMediumRequest that works with an HTTP medium."""

    def __init__(self, medium):

        smart.SmartClientMediumRequest.__init__(self, medium)

        self._buffer = ''

    def _accept_bytes(self, bytes):

        self._buffer += bytes

    def _finished_writing(self):

        data = self._medium.send_http_smart_request(self._buffer)

        self._response_body = data

    def _read_bytes(self, count):

        return self._response_body.read(count)

    def _finished_reading(self):

        """See SmartClientMediumRequest._finished_reading."""

        pass

#---------------- test server facilities ----------------

# TODO: load these only when running tests

class WebserverNotAvailable(Exception):

    pass

class BadWebserverPath(ValueError):

    def __str__(self):

        return 'path %s is not in %s' % self.args

class TestingHTTPRequestHandler(SimpleHTTPServer.SimpleHTTPRequestHandler):

    def log_message(self, format, *args):

        self.server.test_case.log('webserver - %s - - [%s] %s "%s" "%s"',

                                  self.address_string(),

                                  self.log_date_time_string(),

                                  format % args,

                                  self.headers.get('referer', '-'),

                                  self.headers.get('user-agent', '-'))

    def handle_one_request(self):

        """Handle a single HTTP request.

        You normally don't need to override this method; see the class

        __doc__ string for information on how to handle specific HTTP

        commands such as GET and POST.

        """

        for i in xrange(1,11): # Don't try more than 10 times

            try:

                self.raw_requestline = self.rfile.readline()

            except socket.error, e:

                if e.args[0] in (errno.EAGAIN, errno.EWOULDBLOCK):

                    # omitted for now because some tests look at the log of

                    # the server and expect to see no errors.  see recent

                    # email thread. -- mbp 20051021. 

                    ## self.log_message('EAGAIN (%d) while reading from raw_requestline' % i)

                    time.sleep(0.01)

                    continue

                raise

            else:

                break

        if not self.raw_requestline:

            self.close_connection = 1

            return

        if not self.parse_request(): # An error code has been sent, just exit

            return

        mname = 'do_' + self.command

        if getattr(self, mname, None) is None:

            self.send_error(501, "Unsupported method (%r)" % self.command)

            return

        method = getattr(self, mname)

        method()

    if sys.platform == 'win32':

        # On win32 you cannot access non-ascii filenames without

        # decoding them into unicode first.

        # However, under Linux, you can access bytestream paths

        # without any problems. If this function was always active

        # it would probably break tests when LANG=C was set

        def translate_path(self, path):

            """Translate a /-separated PATH to the local filename syntax.

            For bzr, all url paths are considered to be utf8 paths.

            On Linux, you can access these paths directly over the bytestream

            request, but on win32, you must decode them, and access them

            as Unicode files.

            """

            # abandon query parameters

            path = urlparse.urlparse(path)[2]

            path = posixpath.normpath(urllib.unquote(path))

            path = path.decode('utf-8')

            words = path.split('/')

            words = filter(None, words)

            path = os.getcwdu()

            for word in words:

                drive, word = os.path.splitdrive(word)

                head, word = os.path.split(word)

                if word in (os.curdir, os.pardir): continue

                path = os.path.join(path, word)

            return path

class TestingHTTPServer(BaseHTTPServer.HTTPServer):

    def __init__(self, server_address, RequestHandlerClass, test_case):

        BaseHTTPServer.HTTPServer.__init__(self, server_address,

                                                RequestHandlerClass)

        self.test_case = test_case

class HttpServer(Server):

    """A test server for http transports."""

    # used to form the url that connects to this server

    _url_protocol = 'http'

    # Subclasses can provide a specific request handler

    def __init__(self, request_handler=TestingHTTPRequestHandler):

        Server.__init__(self)

        self.request_handler = request_handler

    def _get_httpd(self):

        return TestingHTTPServer(('localhost', 0),

                                  self.request_handler,

                                  self)

    def _http_start(self):

        httpd = self._get_httpd()

        host, port = httpd.socket.getsockname()

        self._http_base_url = '%s://localhost:%s/' % (self._url_protocol, port)

        self._http_starting.release()

        httpd.socket.settimeout(0.1)

        while self._http_running:

            try:

                httpd.handle_request()

            except socket.timeout:

                pass

    def _get_remote_url(self, path):

        path_parts = path.split(os.path.sep)

        if os.path.isabs(path):

            if path_parts[:len(self._local_path_parts)] != \

                   self._local_path_parts:

                raise BadWebserverPath(path, self.test_dir)

            remote_path = '/'.join(path_parts[len(self._local_path_parts):])

        else:

            remote_path = '/'.join(path_parts)

        self._http_starting.acquire()

        self._http_starting.release()

        return self._http_base_url + remote_path

    def log(self, format, *args):

        """Capture Server log output."""

        self.logs.append(format % args)

    def setUp(self):

        """See bzrlib.transport.Server.setUp."""

        self._home_dir = os.getcwdu()

        self._local_path_parts = self._home_dir.split(os.path.sep)

        self._http_starting = threading.Lock()

        self._http_starting.acquire()

        self._http_running = True

        self._http_base_url = None

        self._http_thread = threading.Thread(target=self._http_start)

        self._http_thread.setDaemon(True)

        self._http_thread.start()

        self._http_proxy = os.environ.get("http_proxy")

        if self._http_proxy is not None:

            del os.environ["http_proxy"]

        self.logs = []

    def tearDown(self):

        """See bzrlib.transport.Server.tearDown."""

        self._http_running = False

        self._http_thread.join()

        if self._http_proxy is not None:

            import os

            os.environ["http_proxy"] = self._http_proxy

    def get_url(self):

        """See bzrlib.transport.Server.get_url."""

        return self._get_remote_url(self._home_dir)

    def get_bogus_url(self):

        """See bzrlib.transport.Server.get_bogus_url."""

        # this is chosen to try to prevent trouble with proxies, weird dns,

        # etc

        return 'http://127.0.0.1:1/'

class HTTPServerWithSmarts(HttpServer):

    """HTTPServerWithSmarts extends the HttpServer with POST methods that will

    trigger a smart server to execute with a transport rooted at the rootdir of

    the HTTP server.

    """

    def __init__(self):

        HttpServer.__init__(self, SmartRequestHandler)

class SmartRequestHandler(TestingHTTPRequestHandler):

    """Extend TestingHTTPRequestHandler to support smart client POSTs."""

    def do_POST(self):

        """Hand the request off to a smart server instance."""

        self.send_response(200)

        self.send_header("Content-type", "application/octet-stream")

        transport = get_transport(self.server.test_case._home_dir)

        # TODO: We might like to support streaming responses.  1.0 allows no

        # Content-length in this case, so for integrity we should perform our

        # own chunking within the stream.

        # 1.1 allows chunked responses, and in this case we could chunk using

        # the HTTP chunking as this will allow HTTP persistence safely, even if

        # we have to stop early due to error, but we would also have to use the

        # HTTP trailer facility which may not be widely available.

        out_buffer = StringIO()

        smart_protocol_request = smart.SmartServerRequestProtocolOne(

                transport, out_buffer.write)

        # if this fails, we should return 400 bad request, but failure is

        # failure for now - RBC 20060919

        data_length = int(self.headers['Content-Length'])

        # Perhaps there should be a SmartServerHTTPMedium that takes care of

        # feeding the bytes in the http request to the smart_protocol_request,

        # but for now it's simpler to just feed the bytes directly.

        smart_protocol_request.accept_bytes(self.rfile.read(data_length))

        assert smart_protocol_request.next_read_size() == 0, (

            "not finished reading, but all data sent to protocol.")

        self.send_header("Content-Length", str(len(out_buffer.getvalue())))

        self.end_headers()

        self.wfile.write(out_buffer.getvalue())